Two new species of the genus Betacixius Matsumura, 1914 from China (Hemiptera, Fulgoromorpha, Cixiidae)

Abstract Two new species of Betacixius Matsumura, 1914 (Fulgoromorpha, Cixiidae), B. latissimus Zhi & Chen, sp. nov. and B. maguanensis Zhi & Chen, sp. nov., are described from Yunnan Province, China. The genus is reviewed and a key to all known species is provided. The females of four Chinese species are described for the first time.

Recent study of some Chinese specimens has found two new species, B. latissimus Zhi & Chen, sp. nov. and B. maguanensis Zhi & Chen, sp. nov., which are described here. Female specimens of four species are also described for the first time. So far, including the two new species, the genus currently now counts for 25 valid species and two subspecies, all distributed in the Palaearctic and Oriental regions (Bourgoin 2020).

Materials and methods
The morphological terminology and measurements follow Bourgoin (1987) and Bourgoin et al. (2015). The morphological terminology of female genitalia follows Bourgoin (1993). Body length was measured from apex of vertex to tip of forewing; vertex length was measured the median length of vertex (from apical transverse carina to tip of basal emargination). Fuchsin staining was used to highlight female genitalia structures studied. External morphology and drawings were made with the aid of a Leica MZ 12.5 stereomicroscope. Photographs were taken with KEYENCE VHX-1000 system. Illustrations were scanned with a CanoScan LiDE 200 flatbed scanner and imported into Adobe Photoshop 7.0 for labeling and figure composition. The distribution map was generated with Google Earth Pro v. 7.3.2 (Google LLC). The dissected male and female genitalia are preserved in glycerin in small plastic tubes pinned together with the specimens.
The type specimens are deposited in the Institute of Entomology, Guizhou University, Guiyang, Guizhou Province, China (GUGC).
Diagnosis. See Zhang and Chen (2011: 48 1A, B, D) moderately sclerotized, with a large nearly dumbbell-shaped wax plate. Anal segment (Fig. 1C) rectangular, widening to apex, 1.1 times wider than long in dorsal view, anal style strap-like. Gonapophysis VIII (Fig. 1E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 1F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.2. Gonoplac (Fig. 1G) rodlike, 3.5 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 1H, I.
Distribution. China (Guizhou, Sichuan, Yunnan). Note. The female genitalia of this species are described and illustrated for the first time.  Fig. 2A, B, D) moderately sclerotized, with a large nearly dumbbell-shaped wax plate. Anal segment (Fig. 2C) rectangular, widening to apex, 1.5 times wider than long in dorsal view, anal style strap-like. Gonapophysis VIII (Fig. 2E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 2F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.1. Gonoplac (Fig. 2G) rod-like, 3.6 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 2H Description. Body length: male 6.9-7.1 mm (n = 2), female 7.2 mm (n = 1). Coloration. General color blackish brown (Fig. 3A-D). Eyes reddish brown, lateral ocelli dark red and median ocellus yellow. Vertex dark brown, pronotum yellowish to blackish brown and mesonotum blackish brown. Face generally dark brown, yellowish white above frontoclypeal suture. Postclypeus yellowish brown and anteclypeus blackish brown. Rostrum generally yellowish brown except darker tip. Forewing semitranslucent, base with a broad transverse band from dorsal margin to sutural margin of clavus; clavus with a blackish brown spot on apical third, an oblique transverse band originating from stigma extending to ventral margin. Hind tibiae yellowish brown and abdominal sternites blackish brown.
Male genitalia. Pygofer (Fig. 3F, G) symmetrical, dorsal margin concave and Ushaped ventrally, widened towards apex; in lateral view, lateral lobes arched extended caudally. Medioventral process triangular in ventral view. Anal segment (Fig. 3F, H) long, tubular, asymmetrical, apical lobes arched extended ventrally in lateral view, left lobe larger than right one, 2.8 times longer than wide in dorsal view; anal style fingerlike, not beyond anal segment. Gonostyli (Fig. 3F, G, I) symmetrical in ventral view; in inner lateral view, apical part extended, apical margin acute. Aedeagus (Fig. 3J-M) in total with four processes. Right side of periandrium with a long spinose process apically, straight for most portion, directed dorsocephalically, apex curved downwards and directed ventrocephalically; left side of periandrium apically with two medium-sized spinose processes, the upper one strongly curved and directed dorsally and the other one slightly curved and directed cephalad. Base of periandrium ventrally with several saw-like teeth. Endosoma slender, structure simple, apically with a small spinose process on left margin.  Female genitalia. Tergite IX (Fig. 4A, B, D) moderately sclerotized, with two connected wax plates, nearly oval. Anal segment (Fig. 4C) rectangular, 1.4 times wider than long in dorsal view, anal style strap-like. Gonapophysis VIII (Fig. 4E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 4F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.4. Gonoplac (Fig. 4G) rod-like, 3.8 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 4H, I.

Distribution. China (Yunnan).
Etymology. The specific name, derived from Latin word meaning the broadest, refers to the forewing with an extremely broad band at apex.
Remarks. Male genitalia of B. latissimus sp. nov. is similar to B. herbaceus Tsaur & Hsu, 1991, but differs in: (1) left side of periandrium with two spinose processes (in B. herbaceus, left side of periandrium with one spinose process); (2) spinose process on right of periandrium curved downwards (in B. herbaceus, spinose process in the same position curved upwards); (3) anal segment asymmetrical (the latter symmetrical); (4) forewing with one blackish brown spot and two bands (the latter without any marking). Supplementary description. Female genitalia. Tergite IX (Fig. 5A, B, D) moderately sclerotized, with a medium-sized, nearly dumbbell-shaped wax plate. Anal segment (Fig. 5C) rectangular, slightly widening to apex, 1.1 times longer than wide in dorsal view, anal style finger-like. Gonapophysis VIII (Fig. 5E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 5F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.1. Gonoplac (Fig. 5G) rod-like, 3.4 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 5H, I.

Betacixius maguanensis
Male genitalia. Pygofer (Fig. 6F, G) symmetrical, dorsal margin concave and U-shaped ventrally, widened towards apex; in lateral view, lateral lobes triangularly extended caudally. Medioventral process triangular in ventral view. Anal segment (Fig. 6F, H) long tubular, symmetrical, apical lobes ventrally pointed, 2.1 times longer than wide in dorsal view; anal style strap-like, not extending beyond anal segment. Gonostyli (Fig. 6F, G, I) symmetrical in ventral view; in inner lateral view, apical part extended, apical margin rounded. Aedeagus (Fig. 6J-M) with three processes. Right side near ventral margin of periandrium apically with a long spinose process, nearly straight, apex directed cephalad; left side near dorsal margin of periandrium with a shorter spinose process curving upwards, apex right-dorsally directed. Base of periandrium ventrally with several saw-like teeth. Endosoma slender, structure simple, apically with a small hook-like spinose process.
Female genitalia. Tergite IX (Fig. 7A, B, D) moderately sclerotized, with a large, nearly dumbbell-shaped wax plate. Anal segment (Fig. 7C) rectangular, 1.1 times longer than wide in dorsal view, anal style finger-like. Gonapophysis VIII (Fig. 7E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 7F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.0. Gonoplac (Fig. 7G) rod-like, 3.8 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 7H, I.
Distribution. China (Yunnan). Etymology. The species name is derived from Maguan County, Yunan Province, where the type locality is located.
Remarks. Male genitalia of B. maguanensis sp. nov. is similar to B. flagellihamus Zhang & Chen, 2011, but differs in: (1) spinose process on right of periandrium nearly straight, directed cephalad (in B. flagellihamus, spinose process on right of periandrium curving dorsally); (2) apical lobes of anal segment pointed ventrally (the latter rounded); (3) forewing without ocellate marking (the latter with a large ocellate marking in apical half ). Supplementary description. Female genitalia. Tergite IX (Fig. 8A, B, D) moderately sclerotized, with two nearly oval wax plates, separated from each other. Anal segment (Fig. 8C) rectangular, widening to apex, 1.1 times wider than long in dorsal view, anal style strap-like. Gonapophysis VIII (Fig. 8E) elongate, and slightly curved upwards. Gonapophysis IX (Fig. 8F) with two middle teeth, distance ratio between distal middle tooth to apex and length of denticulate portion is 2.3. Gonoplac (Fig. 8G) rod-like, 3.8 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 8H, I. Distribution. China (Guangxi, Taiwan). Note. The female genitalia of this species are described and illustrated for the first time.

Discussion
Prior to this study, nothing has been reported on the host plants of Betacixius. Nonetheless, we found these planthoppers most commonly in grass, shrubs, or on bamboo and tree leaves, at elevations up to 2600 m. Unfortunately, there is no knowledge of what plants these planthoppers really feed on, except that B. flagellihamus was collected on Quercus sp. (Fagaceae), which might be the plant on which it feeds.
Based on published data and our field surveys, the distribution of Betacixius is mostly restricted to the Oriental parts of China, Japan, and Vietnam, with B. obliquus Matsumura, 1914, occurring in both Palaearctic and Oriental regions, as the only exception (Fig. 9).
The regional studies on Betacixius in China are not equally efficient at finding species. To date, 23 species are known from China, of which about half that number (12 species) are known from Taiwan and only 12 species have been described from southern mainland China, which is much broader and more variant in ecological complexity compared with Taiwan. Therefore, we believe that additional comprehensive field surveys will find that the diversity of Betacixius in mainland China is doubtlessly richer.